Jan 29, 2015
Testing for SCT

Detecting the sickle cell trait could save an athlete’s life. Here’s what you need to know about the testing process and how to respond to a positive result.

By Scott Anderson

Scott Anderson, ATC, is Head Athletic Trainer at the University of Oklahoma. He is the President of the College Athletic Trainers’ Society and a member of the NATA Inter-Association Task Force on Safety in Football. Also the former Co-Chair of the NATA Inter-Association Task Force on Sickle Cell Trait and the Athlete, he can be reached at: [email protected].

When the NCAA Division I Legislative Council approved a rule requiring that all Division I student-athletes be tested for the sickle cell trait (SCT), as with any change, there were questions. While some have been answered, others linger. Regardless, it’s clear that the testing was approved for good reason. Consider the following numbers:

Since 2000, there have been 21 non-traumatic deaths in NCAA football. Sixteen of them were at the Division I level. Of those 16 deaths, 10 were deemed the result of acute exertional rhabdomyolysis (exertional sickling) in student-athletes with SCT. This means that exertional sickling can be tied to greater than 60 percent of non-traumatic deaths in D-I football, and is the leading cause of death in NCAA football.

Knowing an athlete’s SCT status alone will not necessarily prevent their death. But, if the student-athletes themselves, their sport coaches, strength and conditioning coaches, and athletic trainers are all aware of their status and their increased risk for complications from overexertion, extra precautions can be taken to create an expanded margin of safety.

At the University of Oklahoma, we began testing our student-athletes for SCT soon after E. Randy Eichner, MD, joined our program as Team Internist and raised our awareness about the complications and additional risks student-athletes with SCT face.

We initially tested our student-athletes on a voluntary basis, though we soon made the process mandatory as we felt too much was left to chance when the student-athletes could decline. The test is not only for our student-athletes’ welfare, but it also allows us to share Dr. Eichner’s knowledge about SCT.


SCT testing debuted in 1975 when the NCAA recommended it following the 1974 death of a University of Colorado football player who collapsed during a workout and subsequently died from exertional sickling. Although the recommendation was rescinded in 1992 based on a lack of evidence that testing prevents death, institutions continued testing at varying rates.

A 2006 survey of team physicians in (then-called) Division I-A found that 64 percent of respondents were screening at least some of their student-athletes for SCT during pre-participation exams (PPEs). Two years later, following the death of Rice University football player Dale Lloyd, who died from exertional sickling, the NCAA again recommended athletic departments confirm sickle cell trait status in their student-athletes.

Lloyd’s family sued Rice and the NCAA, and as part of the settlement, Rice was required to submit legislation to the NCAA proposing that testing be required. The legislation was approved and went into effect one year ago. This June, the NCAA Committee on Competitive Safeguards and Medical Aspects of Sports recommended that testing also be instituted in Divisions II and III.

Though carriers of SCT should be identified at birth via a screening process, many who carry the trait don’t know it. A recently published survey reported that only 37 percent of U.S. families were informed of their newborn child’s positive test for SCT. At Oklahoma, where we have identified 21 football players with SCT since we started testing about a dozen years ago, 19 were unaware of their condition. This illustrates why merely asking a student-athlete if they or someone in their family carries SCT or has sickle cell disease is an ineffective screening method resulting in false-negatives. A lab test is definitive.

Fortunately, sensitive and affordable testing is available. The NCAA requires a hemoglobin solubility test to detect the presence of hemoglobin S unless the student-athlete can provide documentation of a past test or signs a waiver opting out of testing. Hemoglobin electrophoresis is a standard confirmatory test as it defines percentages for hemoglobin S, hemoglobin A, and other hemoglobins. Though the NCAA does not require electrophoresis testing, we use it to confirm all solubility positive tests at Oklahoma. The solubility blood test costs about $5 per student-athlete, and electrophoresis costs about $30 per student-athlete.

We have made testing a standard component of every incoming student-athlete’s PPE. The University pays for scholarship student-athletes’ PPEs, including testing for SCT. Non-scholarship student-athletes are usually responsible for the cost of their PPEs.

Testing carries a cost, but so does not testing. Beyond the incalculable cost of a human life lost to exertional sickling is the financial fallout from the death of a student-athlete.

One Division I school recently paid $2 million to settle a lawsuit in the death of a student-athlete due to exertional sickling. On top of the settlement, the school also paid for a $250,000 scholarship endowment, $350,000 in legal defense costs, and $10,000 in other court costs. The potential impact upon the careers of those employed at the school must also be considered. In another case, the athletics director, head athletic trainer, and other athletics administrators were terminated. The head coach accepted early retirement.


Most people are born with two normal hemoglobin genes (hemoglobin A). Carrying SCT means the person has one normal gene, hemoglobin A, and one abnormal gene, hemoglobin S. Hemoglobin S can cause red blood cells to develop a crescent or sickle shape and an adhesive-like property, which can block microvascular blood flow.

This sickling of red blood cells in student-athletes with SCT may be triggered during intense exercise, and death can result if activity is not stopped in time. Exertional sickling can be described in stages.

The first stage includes intense and sustained physical exertion hard and long enough to cause blood oxygen levels to drop low enough to cause sickling. Once the cells begin to sickle, blood flow is restricted (called ischemia) and the student-athlete feels a “cramp.”

The second stage occurs as physical exertion continues despite the onset of ischemia. Skeletal muscle breakdown (rhabdomyolysis) begins. The longer the student-athlete continues exerting him- or herself despite symptoms, the further rhabdomyolysis progresses, which dumps the toxins myoglobin and potassium into the bloodstream. Myoglobin affects kidney function and potassium affects the heart.

There is a caveat to the three-stage process: It’s possible that an athlete could die at stage two. If the lactic acidosis and release of potassium into the bloodstream are profound enough, this can stop the heart and death may occur in an hour or less.

The third and final stage of exertional sickling occurs as myoglobin in the bloodstream (a result of rhabdomyolysis) plugs the kidneys. The kidneys cannot filter potassium from the blood. Blood potassium levels then increase, triggering irregular heart rhythm, which can lead to death.

Student-athletes, coaches, athletic trainers, and physicians need to learn to read and heed the signs and symptoms of exertional sickling. Complaints of cramping or muscle spasms are common in athletics, but if the complaints continue for a period of time, action must be taken. Lower extremity weakness is also common at the onset of rhabdomyolysis. And chest pain and the inability to catch one’s breath are often described at this point.

When you are aware that an athlete has SCT, any signs and symptoms like those described here should always be interpreted as exertional sickling. Sickling should be treated as a medical emergency, and there’s no excuse for not being prepared. Every NCAA school is expected to have an emergency action plan.

Check and monitor vital signs and if the student-athlete lacks responsiveness and/or their vitals decline, call 911. Administer high-flow oxygen with a non-rebreather mask if possible. Cooling may also be advantageous if you can do this before EMS arrives. When EMS is on the scene, tell them you suspect rhabdomyolysis and grave metabolic complications, and of course mention that the athlete has SCT, if they do.

For the student-athlete with SCT, there is value in knowing their status. When one of our student-athletes tests positive, they meet with myself and our team physician. We explain that it is not a disease and those with SCT have a normal life expectancy. We also make sure they understand the complications and risks, as well as the precautions they should take as they participate in sport. Athletes with SCT must understand that modifying factors such as environmental heat, an acute illness, newness to an elevated altitude, incessant pace of workouts, and uncontrolled asthma all increase the intensity of the work and their risk for complications.

Simple, tailored precautions should be implemented for the student-athlete with SCT. Those listed in the Consensus Statement from the NATA Inter-Association Task Force on Sickle Cell Trait and the Athlete, and among those we follow here at Oklahoma, include:

• Sitting out conditioning tests on the first day of practice

• Implementing a slow, paced progression of training that allows for longer periods of rest and recovery between repetitions

• Recognizing that heat stress, dehydration, asthma, illness, and altitude create additional risk

• Stopping activity with the onset of any symptoms.

Armed with the knowledge of student-athlete SCT statuses, sport coaches, strength coaches, and athletic trainers can all set a tone within the program that establishes appreciation and accommodation for student-athletes with SCT. It’s a simple and effective opportunity to expand the players’ margin of safety on the field.

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